Is it that easy? If the USA declares 'no first use' do I believe it? How much more than UK, Russia, China, ... Israel, Pakistan, North Korea?

In fact, only America has ever actually used a nuclear bomb in a real war. On the balancing side, they've had a series of de-escalating disarmament treaties with the former USSR, so could be argued to be heading in the more peaceful direction than counties further down my list.

In the game Civilization I know that Gandhi will always, left to his own devices, eventually nuke me, because of a historical in-game joke. The real world is a lot less predictable.